Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
Rea Ravin
Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States; Celoptics, Rockville, United States
Dan Benjamini
Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States; Center for Neuroscience and Regenerative Medicine, Henry Jackson Foundation, Bethesda, United States
Hellmut Merkle
National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
Dave Ide
National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States; National Institute of Mental Health, National Institutes of Health, Bethesda, United States
Teddy X Cai
Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
Nima S Ghorashi
Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, United States
Ruiliang Bai
Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States; Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
We develop magnetic resonance (MR) methods for real-time measurement of tissue microstructure and membrane permeability of live and fixed excised neonatal mouse spinal cords. Diffusion and exchange MR measurements are performed using the strong static gradient produced by a single-sided permanent magnet. Using tissue delipidation methods, we show that water diffusion is restricted solely by lipid membranes. Most of the diffusion signal can be assigned to water in tissue which is far from membranes. The remaining 25% can be assigned to water restricted on length scales of roughly a micron or less, near or within membrane structures at the cellular, organelle, and vesicle levels. Diffusion exchange spectroscopy measures water exchanging between membrane structures and free environments at 100 s-1.
